Attiny85 Voltage Read

Projects General Guidance
1

Hello to everyone,
I need some help for my project and I hope someone could help me.
I want to pilot a relè by a Led condition:
I have a camera and I want to leave the relè off when the LED is on and the relè ON when the LED is off.
I know that I have, when the led it’s ON 1.76V and -2,90 V when the led is off.
How can o read the +1,76 from the A2 pin in my Attiny85 powered by 5V camera?
I also can do an if value is > 0 do something without know the perfect value.

I know that the + it’s ON constantly and - it’s enable/disabled when the LED is ON/OFF

Best regards
Stefano

2

What is controlling the LED?

Where are you measuring to get those values? A schematic showing all parts and the measuring points would be useful.

3

If You get - 2.90 You likely swapped the multimeter pins plus and minus. Minus 2.90 into any Arduino will be bad.....

Instead of a novell, post schematics, would be a lot better.

4

Please provide schematic before you burn ADC

5

Thanks a lot at everyone for all the help :smiley:
My BAD, i have read again the Measurement
So i have a chinese camera that has this LED red that turn on only at the boot phase.
In this led i have 3 PIN

  1. RED PIN (Used for the BOOT Phase)

  2. GREEN PIN (Used After BOOT Phase)

  3. "+" (Common) (LED PART)

  4. "+" From Power Supply (For Power the ATTINY)

  5. "-" From Power Supply (For Power the ATTINY)

In the BOOT Phase if i put the Multimeter to PIN + and PIN RED i have +1,76V and 1 mA
After the boot succeded i have 0,00.

My scope is to turn on one relay only if PIN+ and PIN RED are 0 (RED LED turned off).

Thanks a lot for all your help
Best Regards
Stefano

6

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